In general, communication devices for providing voice communication services employ techniques for removing environmental noise in order to deliver the caller's voice effectively.
A conventional mobile communication terminal performs a process of removing interference by environmental noise, so as to provide good-quality communication to users. In this case, environmental noise input with a low intensity level is removed or eliminated by simply using a filter, and only voice signals input with a relatively high intensity level are amplified and then transmitted. However, although the conventional technique for removing environmental noise interference has advantage in that, since a filter is used for noise cancelation or noise elimination, it is simple to implement the technique, it has disadvantage in that, since some voice signals are removed together with the environmental noise in case there is the environmental noise is loud, the caller's voice signals delivered to a communication partner may be discontinuous.
With the technical development, the function modules built in a mobile communication terminal are becoming more and more high-performance and miniaturized, and with the diversification of users' demands, various functions, such as a camera, an MP3, etc., are additionally built in the mobile communication terminal, some of which comprise functions of external voice recording or phone conversation recording. The function for recording external voice or phone conversation is executed by selection of a separate menu provided in the mobile communication terminal. The user has to open the folder or the slider of a mobile communication terminal to select the corresponding function from the menu. However, because the microphone for sound input is hidden when the folder or the slider is closed, the user is inconvenienced by having to open the folder or the slider of the mobile communication terminal in order to record voice or other sound.